style: Apply nixpkgs-fmt and fix

Apply standard formatting and some statix conventions using;

```sh
nixpkgs-fmt **.nix && statix fix .
```

With the intent of making contribution a bit easier and reducing mental
load in hand formatting (in the same vein as [black]).

[black]: https://github.com/psf/black#the-uncompromising-code-formatter

example/with-lib.nix

@@ -1,7 +1,7 @@
 # Example to create a bios compatible gpt partition
 { disks ? [ "/dev/vdb" ], lib, ... }: {
   disk = lib.genAttrs [ (lib.head disks) ] (device: {
-    device = device;
+    inherit device;
     type = "disk";
     content = {
       type = "table";